1. Field of the Invention
The invention relates generally to kilns and is more specifically directed to solar energized ovens or chambers for thermally processing substances or objects as for cooking, drying, curing, carbonizing, etc.
2. DESCRIPTION OF THE PRIOR ART
Solar energized ovens are known to comprise insulated enclosures into which sunlight may be directed through translucent window-like closure panels for heating the air within such ovens. The air serves as a working fluid for conductive transfer of heat to a substance introduced within such an enclosure, such as food to be cooked. Such art is taught in U.S. Pat. Nos. 4,446,854 and 4,130,106 to Clevett; and 3,391,688 to Dery. One problem with such ovens is that air represents a relatively inefficient heat transfer medium so that even though the air may be quite hot, the transfer of heat from the air to the material to be heated is poor and consequently time-consuming. The heat transfer problem from heated air is exacerbated by the fact that solar heaters or cookers are sealed to prevent loss of hot air and consequently the air in the chamber tends to be stagnant. Thus, a boundary layer of cooler air forms at the interface between the relatively cool substance or object to be heated and the static surrounding hot air mass, such boundary layer thus ihibiting conductive heat transfer to the material to be heated.